Internal combustion engine



Ap 1934- L. M. WOOLSON 1,954,163

' INTERNAL COMBUSTION ENGINE Filed June 28, 1929 2 Sheets-She s: 1

gnbeh'rou LIUNEL M Marian flatl' 1.. M. WOOLSON 1,954,163 INTERNALCOMBUSTION ENGINE April 10, 1934.

Filed June 28, 1929 2 Sheets-Sheet 2 amnion Lzamsz, M Human PatentedApr. 10, 1934 v UNITED STATES- INTERNAL COMBUSTION ENGINE Lionel M.Woolson, Detroit, Mich., assignor to Packard Motor Car Company, Detroit,Mich, a corporation of Michigan Application June 28, 1929, Serial No.374,368

24 Claims.

This invention relates to internal combustion engines, and moreparticularly to engines of the compression ignition type.

Difficulty is encountered in starting engines of the type in whichcombustion of the fuel charge occurs through heat of compression becausethe cylinders are cold. Further, with such engines employed as the powerplant in an airship the same difficulty is encountered when gliding orwhen the fuel quantity is set at the minimum if one or more of thecylinders stop firing, as the air entering the cylinders under theseconditions tends to chill the working chamber, and this occurs even whenglow plugs or a similar electrical heating means is employed. An objectof my in vention; therefore, is to automatically promote the developmentof heat by compression under such conditions in order to raise thetemperature in engine cylinders when starting or idling.

A further object is to provide an internal combustion engine of thecompression ignition type in which temperature in the cylinders isautomatically regulated by and inversely to the engine speed.

Another object of my invention is to provide compression ratio changingmechanism for an internal combustion engine of the compression ignitiontype which is actuated from the crankshaft to vary the compression ratioinversely relative to the speed developed.

Other objects of the invention will appear from the followingdescription taken in connection with the drawings forming a part of thisspecification, in which:

Figure 1 is an end elevation of' an engine, partially broken away andpartially in section, with which my invention is incorporated.

Figure 2 is a vertical sectional view of the same taken on line 2--Z ofFigure 1.

Figure 3- is a fragmentary view of the crank shaft looking at the end ofthe crank cheek.

Referring to the drawings by characters of reference, 10 represents abarrel-like crank case having an axial hub 11 through which the singlethrow crank shaft 12 extends. Bearings 13, 14, and 15 are arrangedintermediate the crank case and crank shaft, and a propeller 16 issecured to the front end of the crank shaft whichprojects beyond thecrank case. Cylinders 1! extend radially from the crank case, and aresecured rigidly therewith by compression hoops 18 which encircle flangeportions of the cylinders to clamp them under compression against thecrank case.

A piston 19 is reciprocably mounted within each of the cylinders, amaster rod 20 being connccted with the uppermost piston. Connecting rods21 are secured to the other pistons and are pivoted to the master rodhub 22, in circular arrangement, by pins 4 23.

between the cheeks 25.

The internal combustion engine illustrated is The master rod hubencircles the crank shaft pin 24 which extends cf the four-cycle type inwhich air and liquid fuel are introduced separately into the cylinders,and mixed therein to form a, fuel charge which is ignited by the heat ofcompression. For this purpose any conventional manner of air and fuelintroduction can be utilized, however, I have shown the cylinderprovided with a Vcnturi passage 26 in the cylinder head which isarranged to direct the air against the working .chambcr wall so that itwill be caused to rotate in the A valve 27 controls the air passage, andin this instance I utilize the passage as the cylinder.

exhaust outlet as well as the inlet, andsuitable actuating mechanism isarranged between the valve rocker arm 28 and the crank shaft. A highpressure fuel injection device is attached to each ozzle portion 29 andcylinder and consists of a a pump portion ,30, suitab e mechanism foroperating the pump rod 31 being actuated intermittently from the crankshaft. Fuel is conducted to the pumps from a reservoir in any suitablemanner, such as by conduit means 50.

In order that starting of the engine and bringing in of cylindcrswhichhave ceased firing while the engine is idling may be assisted, I providemeans for automatically increasing the temperature in the cylinders.There are various ways of accomplishing this result, the specificembodiment shown consisting of a speed actuated compression ratiochanging mechanism associated with the master rod and the crank shaft.The

device is arranged so that the compression ratio is varied automaticallyinversely to the speed of the engine, so that when idling thecompression ratiois the highest, and when running under full fuelinjection or load the compression ratio is the lowest.

To this end I provide a three part eccentric sleeve 32 intermediate thecrank shaft pin 24 and bolt-33. The eccentric sleeve 32 is provided ateach end with eccentric flanges 34 which are positioned adjacent thecrank shaft cheeks, such ec centric flanges providing bearings for theyoke members 35 which extend adjacent the crank cheeks in the sameplanes with the flanges. For the purpose of assembly, the eccentricsleeve 32 is formed in three axially arranged sections, the centralsection 36 providing a spacer for the flanged. pieces. The center of thecrank pin is indicated at A, the center of the eccentric sleeve and themaster rod hub mounted thereon isindicated at B, and the center of theeccentric flanges is indicated at C. It will be seen, therefore, thatthe center of both the sleeve flanges and master 'rod hub are in anoff-center relation with the crank pin, and that turning of theeccentric in its relation to the crank pin will shift the master rodrelative to the crank pin and thereby change the piston stroke and thecompression ratio.

The crank shaft cheeks are each provided with a plurality of bores 37which are closed by screw plugs 38 from the inner face of which stopmembers 39 extend. The cheeks are also provided with slots 40, extendingin a direction transversely to the bores therein, to accommodate pins41.

A bearing member 42 is arranged within each of the cheek bores and suchmembers provide seats for one end of the coil springs 43 which arearranged within the bores so that they encircle the stop members andengage the plugs 38 at their other ends. It will be seen that the springtension can be regulated through adjustment of the screw plugs, so thata desired pressure will normally be exerted against the bearing membersand the pins, and it will be further seen that the stop members 39 limitthe movement of the pins 41 in a direction compressing the springs.Movable counter weights for the crank shaft are utilized for actuatingthe compression ratio changing mechanism. The weight members 44' aresecured to the yoke members35 by nuts 45, and a pair of stops 46 extendfrom the weight members and are secured to the ends of the pins 41. Thecrank cheeks are provided with slots 4'7 which provide guide-ways forthe ends of the nuts projecting through the yokes.

When the rotational speed of the crank shaft is at the minimum, as whenthe engine is idling, the mechanism is in the relation shown in Figure2. As the speed increases, the weight members are moved by centrifugalforce in a direction toward the ends of the crank cheeks remote from thecrank pin, so that when the crank shaft speed increases and a sufflcientcentrifugal force is developed to overcome the tension of the springs43, the weights and attached pins will move outwardly. Such movement ofthe counterweights will cause the yokes to be moved therewith throughtheir attachment, carrying the eccentric in an anti-clockwise directiontherewith as viewed from the rear of the engine, thereby shifting thecenter of the master rod in the same direction relative to the center ofthe crank shaft pin. Such change of the master rod relation with thecrank pin will shorten the reciprocal movement of the pistons and willalso increase the cylinder clearance space thereabove when in top centerposition, therebyreducing the compression ratio.

As the engine speed is reduced the springs will normally return thestructure to a position producing higher compression ratio. The springsare preferably placed under suflicient tension so that the engine willhave to be rotating at a speed sufflcient to sustain an aeroplane inflight before the centrifugal force will cause compression of thesprings and allow the device to function.

It will be seen that the mechanism is arranged to automatically providethe highest compression ratio when the engine is working at low speedand to decrease the compression ratio as the speed increases. As thecylinder temperature is greater at a high compression ratio, starting ofthe engine and bringing in of the cylinders which have ceased firingwill be greatly facilitated. This invention is of especial'assistancewith engines in which air, for the fuel charge, is drawn directly intothe cylinders and in which ignition occurs through heat of compression,because air being drawn in tends to cool the cylinders.

It will be seen that the shaft counter weights are utilized to actuatethe compression ratio changing mechanism. The invention is of especialadvantage in raising the temperature in the cylinders when an engine isidling during gliding of an aeroplane, because with normal compres sionratio, the fuel charge is small and the incoming air, which is usuallycolder with elevation, tends to chill the cylinder and thus reduces thetemperature to such an extent that combustion will not occur and isdimcult to renew.

Various changes can be made in the details of the structure illustratedand described without departing from the spirit of my invention and thescope of what is claimed.

What I claim is:

1. In an internal combustion engine, a crank shaft, an eccentricrotatable on the crank shaft pin, a piston connecting rod engaging saideccentric, and mechanism for automatically actuating said eccentric tocontrol the rod movement and thereby regulate the compression ratioinversely to engine speed, said mechanism including resilient meansassociated to oppose the rotation of the eccentric in one directionrelative to the crank shaft pin.

2. In an engine, a crank shaft, and automatic compression ratio varyingmechanism responsive to the speed of the crank shaft, said mechanismbeing carried entirely by and rotatable with said crank shaft andoperating to vary the compression ratio inversely with the speed of thecrank shaft.

3. In an engine, a crank shaft, an eccentric sleeve mounted on the crankshaft pin, said sleeve having eccentric flanges, means engaging saidflanges responsive to engine speed for rotating the eccentric on thecrank pin, and a piston connecting rod mounted on the eccentric sleeve.

4. In an engine, a crank shaft, an eccentric sleeve mounted on the crankshaft pin, said sleeve having end eccentric flanges, members alignedwith the crank cheeks and mounted around the eccentric flanges, andmeans associated with the members and reciprocating in response to thespeed of the shaft to shift the members and rotate the sleeve relativeto the pin to vary the stroke of the piston rod. 5. In an engine, acrank shaft, an eccentric sleeve formed of aligned sections mounted onthe crank pin, the end eccentric sections having eccentric flangesextending therefrom, a piston-connecting rod carried by said eccentricsleeve, and means responsive to the crank shaft speed and associatedwith the eccentric sleeve flanges to control the rotational position ofthe sleeve with respect to said crank pin.

6. In an engine, a crank shaft, an eccentric sleeve rotatably mounted onthe crank pin, eccentric flanges extending from the ends of said sleeveadjacent the crank shaft cheeks, a piston connecting rod carried by theeccentric sleeve, weighted strap members adapted to reciprocate alongthe crank shaft cheeks and encircling the eccentric flanges, said strapmembers reciprocating in accordance with the crank shaft speed, andspring means resisting such movement of said weighted strap members.

7. In an engine, a crank shaft, movable counterweights associated withthe crank shaft cheeks, and mechanism actuated by the counterweights toregulate the compression ratio.

8. In an engine, a crank shaft, an eccentric sleeve rotatably mountedupon the crank pin, a piston connecting rod mounted on the eccentricsleeve, members for rotating the eccentric sleeve on the crank pin, andcounterweights associated with the crankshaft cheeks, saidcounterweights being movable responsive to the speed of the crank shaftrotation to move said members, re-

. silient means resisting centrifugal movement of said counterweights,and means limiting the movement of said counterweights.

9. In an internal combustion engine, a crank shaft, centrifugallymovable counter weights for v the crank shaft, a connecting rod,assembly of the engine.

mounted on the crank shaft, and means actuated by the movement of saidcounter weights for varying the relation of the connecting rod assemblyon the'crank shaft to regulate the compression ratio 10. In an engine,'acrank shaft, movable counterweights associated with the crank shaftcheeks, and mechanism actuated by the counterweights to regulate thecompressionratio inversely to the engine speed.

11. The method of charging an internal combustion engine comprisingintroducing air charges into the cylinders in quantities varyinginversely with the engine speed, compressing the air charges to anextent varying in accordance with the quantity thereof, and introducingfuel charges into the compressed air charges in the cylinders. v a

12. The method of charging an internal combustion engine comprisingintroducing air charges into the cylinders in quantities varyinginversely with the engine speed, compressing the air charges to themaximum when the engine is running below a predetermined R. P. M.,reducing the compression pressure as the R. P. M. increases above thepredetermined amount, and introducing atomized liquid, fuel into thecompressed air charges.

13. In an internal combustion engine, compression ratio regulatingmechanism, means normally urging said mechanism into a position causingthe maximum compression of fuel charges, and means responsive to enginespeed beyond a predetermined R. P. M. for actuating the mechanism tovary the compression ratio inversely with the speed.

14. In an internal combustion engine, com pression ratio regulatingmechanism, means responsive to centrifugal force for actuating themechanism to vary the compression ratio inversely with the engine speed,and means opposing the eifectof centrifugal force to actuate themechanism, saidopposing means being effective to prevent actuation 01*said mechanism below a predetermined engine speed.

15. The method of operating an internal combustion engine comprisingintroducing air charges by suction into the cylinders in a volumedetermined by thepiston stroke, compressgine operation, compressing theair charges ining the air charges in the cylinders, introducing fuelcharges into the compressed air charges in desired volume, and varyingthe range of the piston stroke throughout one portion only of the enginespeed range.

16. The method of operating an internal combustion engine comprisingintroducing air charges by suction into the cylinders in a volumedetermined by the piston stroke, compressing the air charges in thecylinders, introducing fuel charges into the compressed air charges indesired volume, and varying the range of the piston stroke throughoutone portion only of the engine speed range and inversely to the enginespeed.

17. The method of operating an internal combustion engine comprisingintroducing air charges into the cylinders varying in volume inverselywith the speed in the higher range of engine operation, compressing theair charges in the cylinders, introducing fuel charges into thecompressed air charges in desired volume, and varying the compressionratio throughout the higher speed range of the engine inversely with thespeed variance.

18. The method of operating an internal combustion engine comprisingintroducing air charges into the cylinders varying in volumeinverselywith the speed in the higher range of entroduced into the cylinders,introducing fuel charges into the compressed air charges in thecylinders, and adjusting the movement range of a wall of the combustionchambers to vary the compression ratio inversely with and above a predetermined speed.

19. In a radial type explosion engine, the combination with the crankshaft and master connecting rod hub, of a compression ratio changingdevice comprising an eccentric sleeve inter- 1 mediate the crank shaftand the master rod hub, and automatic means carried entirely by thecrankshaft for adjusting the position of the eccentric sleeve upon andin a direction relative to the crank shaft whereby the hub is shifted tocause a compression ratio varying inversely relative to .the enginespeed.

1 20. In an internal combustion engine, a crank shaft, aneccentricrotatable on the crank shaft pin, a piston connecting rod hubcarried by said eccentric, means responsive to engine speed andconnected to the eccentric for rotating the same relative to the pin toregulate the compression ratio inversely to engine speed, and springmeans resisting the movement of the eccentric from a position effectinghigh compression ratio.

21. The method of charging an internal combustion engine, comprisingintroducing air charges into the cylinders, compressing the air chargesin the cylinders, introducing atomized liquid fuel into the compressedair charges in the cylinders to form a combustible mixture, maintaininga constant high compression ratio below a predetermined engine speedrange, and regulating the compression ratio above the predeterminedspeed range inversely with the variance thereof.

22. In a. radial engine, a crank shaft, an eccentric sleeve rotatablymounted on the crank shaft, cylinders, pistons in the cylinders, aconnecting rod assembly associated with the pistons and including a hubmounted on the sleeve, and regulating mechanism connected to the sleeveto control its position angularly on the crank shaft 7 saidmechanismautomatically turning the sleeve on the crank shaft to shiftthe hub in a direction to regulate the compression ratio inversely tothe engine speed.

23. The method 01' charging an internal combustion engine comprisingdrawing air charges into the cylinders through suction induced bypistons, varying the volume of the air charges drawn into the cylindersinversely with the engine speed, compressing the air charges drawn intothe cylinders to an extent varying directly as the volume thereof, andintroducing atom'med liquid

